Exam 2: Methods for Describing Sets of Data

The mean and the median are useful measures of central tendency for both qualitative and quantitative data.

Many firms use on-the-job training to teach their employees computer programming. Suppose you work in the personnel department of a firm that just finished training a group of its employees to program, and you have been requested to review the performance of one of the trainees on the final test that was given to all trainees. The mean of the test scores is 74. Additional information indicated that the median of the test scores was 84. What type of distribution most likely describes the shape of the test scores?

The following data represent the scores of 50 students on a statistics exam. The mean score is 80.02, and the standard deviation is 11.9. 39 51 59 63 66 68 68 69 70 71 71 71 73 74 76 76 76 77 78 79 79 79 79 80 80 82 83 83 83 85 85 86 86 88 88 88 88 89 89 89 90 90 91 91 92 95 96 97 97 98 Find the z-scores for the highest and lowest exam scores.

If a sample has mean 0 and standard deviation 1, then for every measurement x in the sample the z-score of x is x itself.

The process for finding a percentile is similar to the process for finding the median.

Which of the graphical techniques below can be used to summarize qualitative data?

An outlier is defined as any observation that falls within the outer fences of a box plot.

What characteristic of a Pareto diagram distinguishes it from other bar graphs?

An outlier may be caused by accidentally including the height of a six-year-old boy in a set of data representing the heights of 12-year-old boys.

The scores of nine members of a women's golf team in two rounds of tournament play are listed below. Player 1 2 3 4 5 6 7 8 9 Round 1 85 90 87 78 92 85 79 93 86 Round 2 90 87 85 84 86 78 77 91 82 Construct a scattergram for the data.

Calculate the range of the following data set: 9, 6, 9, 2, 8, 10, 6, 6, 9

By law, a box of cereal labeled as containing 18 ounces must contain at least 18 ounces of cereal. The machine filling the boxes produces a distribution of fill weights with a mean equal to the setting on the machine and with a standard deviation equal to 0.03 ounce. To ensure that most of the boxes contain at least 18 ounces, the machine is set so that the mean fill per box is 18.09 ounces. Assuming nothing is known about the shape of the distribution, what can be said about the proportion of cereal boxes that contain less than 18 ounces.

Which number on the screen below is the sample standard deviation of the data?

The box plot shown below displays the amount of soda that was poured by a filling machine into 12 -ounce soda cans at a local bottling company. Based on the box plot, what shape do you believe the distribution of the data to have?